There is known in the art an ink cartridge that can be detachably mounted in a mounting unit of a recording device for supplying ink to a recording head of the recording device. Attached to the ink cartridge is a circuit substrate having storing means for storing data indicating information on the ink cartridge, such as quantity of ink remaining in the cartridge, color of ink accommodated in the cartridge, and the like. When the ink cartridge is mounted in the recording device, electrodes provided on the circuit substrate form an electrical connection with device-side terminals provided in the recording device. This electrical contact between electrodes and device-side terminals allows the recording device to access the storing means of the circuit substrate.
In this type of ink cartridge, positioning of the circuit substrate on the ink cartridge is performed by inserting a plurality of protrusions provided on the cartridge through a plurality of holes formed in the circuit substrate. The circuit substrate is fixed to the cartridge by thermally caulking the protrusions.
One conventional technology for fixing the circuit substrate to the cartridge involves thermally caulking of the protrusions inserted through the holes of the substrate at positions before and after electrodes on the substrate with respect to a direction in which the ink cartridge is inserted into the recording device.